1. Field of the Invention
The present invention relates to a process for preparing 4-amino-3-methyl-N-substituted or unsubstituted alkylanilines, and more particularly, relates to a process for preparing these alkylanilines from 4-amino-3-methyl-nitrobenzene, in which the amino group of the starting 4-amino-3-methyl-nitrobenzene is protected, for example, by tolenesulfonylation, phthalylation or acetylation, the nitro group of the nitrobenzene is hydrogenated and then alkylated, and thereafter the intermediate is hydrolyzed. The products can be converted, if desired, to salts using inorganic or organic acids.
2. Description of the Prior Art
N,N-disubstituted paraphenylene-diamines are important compounds as color developing agents for color photography. In particular, paraphenylene-diamines having a methyl group ortho to the primary amino group are especially important compounds.
Various processes have heretofore been proposed for the production of 4-amino-3-methyl-N-substituted alkylanilines which are commercially available color developing agents for color photography, and of these processes, those disclosed in Journal of the American Chemical Society, 73, 3100- 3125 (1951) and in Japanese Patent Laid-Open Application Nos. 11534/72 and 11535/72 are particularly popular.
m-Toluidine which is a starting material for the above method is prepared by nitration of toluene and reduction of the m-nitrotoluene produced. In practice, however, m-nitrotoluene corresponds to a mere by-product obtainable in the nitration step of toluene only in an amount of about 3%. Therefore, the yield of m-nitrotoluene is too small and the supply and demand thereof are very often not balanced. Under such circumstances, the above-mentioned process for preparing paraphenylenediamines starting from m-toluidine is not a stable industrial method from the standpoint of cost and the nature of the starting material.